This version is outdated by a newer approved version.
This version (16 Oct 2018 22:15) is a draft.
Approvals: 0/1
This version (16 Oct 2018 22:15) is a draft.Approvals: 0/1
This is an old revision of the document!
Table of Contents
FFT Analysis Features
ACE includes the ability for plug-ins to use a full-featured FFT analyzer. The details of the implementation and the specific user interface depend on the plug-in for a specific product, but the AD9208 will be used to demonstrate the features of the analyzer.
Running Analysis and Viewing the Results
The FFT can be run in “Run Once” or “Run Continous” modes. With the “Run Once” mode the capture history will be stored and the user can navigate to previous captures and their associated analysis. The currently selected analysis can be re-run allowing the user to change the values in the Analysis Settings Wizard.
Setting the fundamentals
There are three modes available for finding the fundamentals, for the AD9208 these can be set in the Analysis Wizard.
- Highest Bin - Set the fundamentals to the highest spurs. This is the legacy behavior and a good
default
- Mirror Image - Set spurs to the highest bin of the values in the Analysis Wizard and their mirror images.
- Fixed - Set spurs locations in the Analysis Wizard.
Adjusting Window and Spectral Leakage Compensation
For non-coherent signals it is necessary to apply a windowing function. However, windowing causes spectral spreading around the spurs, requiring spectral leakage compensation. ACE performs windowing and spectral leakage compensation by default for the AD9208 using the recommended settings, however the user is able to modify these settings if there are specific requirements.
Two Tone Analysis
Two tone analysis will automatically find the two highest spurs and set them as fundamentals. The harmonics and inter-modulation distortion spurs will be found automatically. Only the spurs above the noise floor will be marked.
Averaging FFT
The FFT analysis can only be run in “Run Continuous” mode. The graph view will show a countdown as the required samples are captured, and a FFT spectrum will be displayed once the data is valid. You can stop the “Run Continuous” capture and inspect export the data when desired.
To save memory, you can de-select the Averaging FFT when it is not needed using the checkbox next to the AveragingFFT icon.
resources/tools-software/ace/fftanalysis.1539720959.txt.gz · Last modified: 16 Oct 2018 22:15 by Matt McCarn